Add support for entering/exiting HTML fullscreen from OOPIFs.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 267eeb8e5360f38c727800484ca4396897bf36ff..91010161d1e5cdeaf24bb34b8b2612c9bb16852e 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1865,9 +1865,6 @@ void WebContentsImpl::ExitFullscreenMode(bool will_cause_resize) {
 
 bool WebContentsImpl::IsFullscreenForCurrentTab(
     RenderWidgetHostImpl* render_widget_host) const {
-  if (!RenderViewHostImpl::From(render_widget_host))

[alexmos, 2016/05/10 21:36:24]

Removing this allows subframe widgets to pick up the is_fullscreen_granted bit
when sending ViewMsg_Resize. (This is used in RWHI::GetResizeParams.)  

I've checked all other uses of this, and they all pass in an RVH's widget, so
this should be safe.  In fact, the |render_widget_host| param is now
unnecessary, but I'd like to remove it in a follow-up CL, since it affects a
bunch of unrelated files.

[Charlie Reis, 2016/05/12 22:59:23]

Ok.  Let's put a TODO to remove it.

-    return false;
-
   return delegate_ ? delegate_->IsFullscreenForTabOrPending(this) : false;
 }